1. Technical Field of the Invention
The present invention relates in general to a curb that is mounted on a roof of a building and is used to support air moving equipment such as an air conditioner or any other type of rooftop appliance.
2. Description of Background and Related Art
It is well known that roof curbs are used as a mounting structure for air moving equipment and other types of rooftop appliances which are located on a roof of a building. Traditionally, roof curbs where specifically designed and custom made to provide a relatively horizontal mounting structure for a particular rooftop appliance given the shape and pitch of a particular roof. Of course, designing and building these traditional roof curbs which were often one piece of metal that was custom fabricated to the particular roof pitch was a laborious and time consuming task for the manufacturers and installers of the rooftop appliances. Thus, adjustable roof curbs were developed to mount rooftop appliances on various types of roofs that have different pitches without custom making one piece roof curbs for each type of pitched roof. Two examples of known adjustable roof curbs are briefly described below with respect to FIGS. 1 and 2.
Referring to FIG. 1, there is illustrated a known adjustable roof curb 100 similar to one currently manufactured by MicroMetl Corporation. Generally, the adjustable roof curb 100 includes a bottom section 102 secured to a roof 104 and a top section 106 used to mount a rooftop appliance 108. The top section 106 is designed to slide over the bottom section 102 in a manner such that the top section can be positioned to provide a relatively level support (e.g., horizontal support) for mounting the rooftop appliance 108. After leveling the top section 106, the bottom section 102 is secured to the top section by inserting screws into pre-punched holes 110 (ten shown) that are positioned around the lower portion of the top section 106. This type of adjustable roof curb 100 can be a safety hazard because the screws are susceptible to failure due to the load (e.g., shearing load) of the rooftop appliance 108. Failure of the screws can be accelerated due to weather degradation and vibration of the roof top appliance.
Referring to FIG. 2, there is illustrated another known adjustable roof curb 200 similar to one described in U.S. Pat. No. 4,917,345. Generally, the adjustable roof curb 200 includes a base member 202 secured to a roof 204 and a support member 206 used to mount a rooftop appliance 208. The base member 202 includes at least two slotted apertures 210 (three shown) and the support member 206 also includes at least two slotted apertures 212 (two shown) for alignment with the apertures 210 formed within the base member 202. The apertures 210 and 212 enable the adjustable coupling of the support member 206 to the base member 202 to provide a level support for mounting the rooftop appliance 208. After leveling the support member 206, the base member 202 is secured to the support member 206 by inserting fasteners 214 (e.g., threaded bolts) into the aligned slotted apertures 210 and 212. To further secure the base member 202 to the support member 206, screws can be inserted into the base member 202 by passing them through apertures 216 (eleven shown) positioned around the lower portion of the support member 206. This adjustable roof curb 200 can also be a safety hazard because the threaded bolts 214 can loosen (e.g., due to vibration of the rooftop appliance 208 ) and slide-down the apertures 210 and 212. Without the load bearing capacity of bolts 214, the screws in aperture 216 now bear the load of the rooftop appliance 208. The screws in apertures 216 may then fail due to shear loading. Failure may be accelerated by weather degradation and vibration of the rooftop appliance. Thus, there is a need for an adjustable roof curb and method of use that addresses the safety hazards and other problems associated with traditional adjustable roof curbs.
The present invention is a method and an adjustable roof curb that addresses the deficiencies of the prior art by safely supporting a rooftop appliance. Additionally, the present invention can be quickly assembled on the job site, saving time and installation costs over customized roof curbs or known prior art adjustable roof curbs. More specifically, the adjustable roof curb includes a base curb section, a support curb section and at least one pin operating as a fulcrum to adjustably position the support curb section to a desired pitch relative to a pitch of the base curb section, and further operating to effectively bear a load of the rooftop appliance (e.g., fan, air conditioner) mounted on the support curb section.